Air inlet device for internal-combustion engines



April 7, 1953 0. v. BERHOUDAR 2,633,868

AIR INLET DEVICE FOR INTERNAL-COMBUSTION ENGINES Filed Sept. 22, 1950 TO VENTURI 25 7 THROAT INVENTOR:

05 E P V- BERHOUDHR 3W BY ATTO RM 51 Patented Apr. 7, 1953 AIR INLET DEVICE FOR INTERNAL- COMBUSTION ENGINES Osep Va'han" Berhoudar, Johannesburg, Transvaal, Union of South Africa Application September 22, I950, Serial'No..186,239 In the Union of South Africa September v26, 1949 1 Claim. (Cl. 137-480) This invention relates to a device to provide in conjunction with a carburettor a secondary air supply for the induction system of an internal combustion engine.

It is known that carburettors 'forinternal combustion engines supply a fuel-air mixture which becomes increasingl'y rich as the engine load m- I creases. To counteract such enrichment devices have. been proposed for admitting a supply of uncarburetted air to theinduction system of the engine; 7 Generally these devices comprise a spring loaded pressure responsive diaphragm or pistony operatingto open or closea valve, controlling the supply. of unc'arburetted air. These devices have been found not to be fullyv effective for one or allof the following reasons; The required amount oi uncarburetted a-ir supplied to'the fuel-air-mixture does not increase in the same proportion as the engine revolutions; very rapid and correct response to'small changes in engine requirements is prevented by excessive friction of the piston operated valve and also by the inertia of the spring. loading. the piston or diaphragm, and

finally the devices will not giverthesame responseunder varying atmospheric pressure conditions because the degree of spring loading on the piston or diaphragm does not vary accordingly.

-It is generally the object of this invention to I provide an uncarburetted air inlet device which will overcome these disadvantages. I

, Acc-ordingly this invention provides a device operating to'supply a regulated quantity of uncarburetted air into the induction system automatically as and when required. The device comprises a casing containing a double valve and valve seats; an inlet for atmospheric air below one valve and above the other; the valves being so shaped and proportioned that the static pressures on them are substantially balanced when they are closed; an outlet port for the air between the valve seats and a pressure responsive diaphragm moved by a differential pressure in the induction system, such movement serving to raise the valves from their seats. According to further features of the invention there are provided means for restricting the dew of air between the one inlet and one side of the diaphragm; the valve stems and valve seats are given a streamline shape and there is provided an oil bath type of air cleaner for the air passing the inlet.

The accompanying drawing shows a preferred form of the device and is a sectional side elevation in a normally operating position.

2 The device consists of a cylindrical casingl with its" top opening into a flattened or 'elliptically shaped chamber 2 divided by a pressure respon- The centre portion 4 of the length of the casing, I is closed by a pair of supersive diaphragm 3.

imposed valve seats hand 6 and a double balanced valve. 7 seating therein. Its stem 3 projects through the top and bottom seats 5 and 6 respectively; The top 9 of the'stem- 8 is attached to the pressure responsive diaphragm 3. The

projecting portions of stem 8 are adapted t0" reciprocate centrally in guides carriedin spiders ll, i2,.the lower part it of, said stem being extended for this purpose. The bottom 13 of the casing, is extended to carry a spider E4 the bottom of which is provided with a projection I5 carrying an oil bowl It.

Atmospheric air enters throughaperture ll between bowl l5 and the casing l and after being cleaned in bowl it enters the casing i through spider l4.

is he channel in the wall of the casing l and allows-a portion of the air entering through H to pass to the top of the casing l and down through spider l l. The flow of air through the channel this controlled by achoke 59 which conveniently is screwed into the channel and held in position by a lock nut 2Q.

21 is an outlet for the air passing the valve seats 5,. 6, and is provided as shown, with aflange 22 forconnecting it to. the induction system of an internal combustion engine. The portion 23 of chamber 2 above the diaphragm 3 is connected to the throat of the venturi of the carburettor by means of a tube (not shown) connecting with nipple 24. If desired the top or" the valve stem 9 may be extended above the top of the chamber 2 to serve as an indicator 25 showing the position of the valves 1. The indicator 25 is seen through a window 26 in the dome 21.

For use, the flange 22 is attached to a suitable adaptor which is fitted between the carburettor and induction manifold so that the latter communicates through the outlet 2| with the chamber 28 between the valve seats 5 and 6. The nipple 24 is connected to the throat of the carburettor, normally by means of flexible pipe.

When the engine is idling with the throttle valve closed there is a reduction in pressure in the induction manifold acting on both valves and the flow of air past the throat or the carburettor will be too slow to provide a reduction in pressure in the top of chamber 2 sufficient to cause the diaphragm 3 to lift. The valves 7 will thus remain closed with the diaphragm 3 in its lowest position.

As the throttle is opened slightly the increased flow of air through the carburettor throat results in suiiicient reduction in pressure to cause the diaphragm 3 to move upwardly and to raise the valves 1 off their seats 5, 6. This slight movement of the valves I from their seats 5, 6 alters the surfaces subjected to air pressures so that the double valve becomes fully balanced. Atmospheric air will flow past the oil cleaner l6, and both upper and lower valve seats 5, B into the induction system through outlet 2|. With the valves 1 partially open the upward movement of the diaphragm 3 by pressure of the atmospheric air, is opposed by the low pressure in the induction manifold and communicated through the outlet 2! and through the valve seat 5 the spider H to chamber 2 below the diaphragm 3. V

As the throttle valve of the engine is opened further there is a greater reduction in pressure in the throat of the carburettor causing the di aphragm 3 to lift still higher and to move the valve 1 further off their seats 5, 6.

The upward movement of the diaphragm 3 is opposed to a lesser extent as it is lifted due to the pressure increase in the induction manifold.

It will be noted that the valves 1 are dimensioned so that the pressures acting on them are substantially balanced. This is a necessary provision since for example, if there was only one valve provided on seat 6 a vacuum in outlet 2| would at once cause the valve to lift and the vacuum would be broken. Conversely, if the lower valve were eliminated and reliance was placed on the valve on seat 5 a vacuum in 2! would tend to hold this valve closed. According to the design of the device there is a greater area of the valve on seat 5 exposed to atmospheric pressure than the lower part of the valve ex posed to the pressure in chamber 28. On the other hand there is a greater area of the valve on seat 6 exposed to the reduced pressure in chamber 28, than the area so exposed on the part of the valve 1 on seat 5. However when the air is moving through the device the balance of the valve 1 can be regulated by controlling the flow of air to spider II by adjustment of the position of the choke Hi. In fact the passage It can be so restricted that the lift of diaphragm 3 will have little or no assistance of the atmospheric air pressure on its lower side.

. The valve stem 8 at 29 and 30 below the upper and lower valve 1 respectively and also the valve seats 5 and 6 above and below the valve seating are shaped as shown so as to provide substantially streamline passages for the air flow about the valves.

The action of the device is responsive to the demand of the engine to which it is attached. If the flow of air through the throat of the carburettor has high velocity the diaphragm 3 will lift the valves 7 from their seats 5, 6 and allow a relatively large volume of air to pass into the induction system which will in turn tend to lessen the flow through the throat until a balance is obtained.

Normally the weight of the valve and valve spindles will be suflicient to prevent any surging, hunting or bouncing of the valves but if necessary a suitable spring may be inserted merely to damp the movement of the valves.

What I claim as new and desire to secure by Letters Patent is:

A device connected to the carburettor and the induction system of an internal combustion engine for supplying air direct to the induction system of the engine comprising a casing with a vertical passageway, a valve seat at each end of said passageway, two valves on a single spindle cooperating with said valve seats, a chamber above said casing divided horizontally with a pressure responsive diaphragm, the valve spindle suspended from the centre of said diaphragm, the casing below the lower valve seat open to atmosphere, a channel for air from below the lower valve to above the upper valve and below the pressure responsive diaphragm, an adjustable check in said channel, an air outlet from said vertical passageway between the two valves and a connection from above the pressure responsive diaphragm to the venturi of the carburettor.

OSEP VAHAN BERHOUDAR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,470,057 Carter Oct. 9, 1923 2,207,152 Huber July 9, 1940 2,326,598 Acosta Aug. 10, 1943 2,327,592 Chisholm Aug. 24, 1943 2,470,098 Mock May 17, 1949 

